Process for producing an antistatic finish on synthetic fibers



United States Patent T This is a continuation in part of our applicationSer. No. 826,146, filed July 10, 1959 (now abandoned).

This invention relates to the treatment of organic, hy-

drophobic, synthetic fibers to impart antistatic properties thereto.

According to the present invention a process for producing a washproofantistatic finish on organic, hydrophobic, synthetic fibrous materialwhich comprises impregnating the said material with an aqueouspreparation containing, per 1,000 parts of water,

(a) 3 to 25 parts of a Water-soluble diglycidyl ether of a polyethyleneglycol having an average molecular weight of 300 to 1500, whichdiglycidylether contains 0.75 to 4.5 epoxide equivalents per kg, and

(b) 0.4 to parts of a water-soluble amine,

squeezing the fibrous material to such an extent that from 0.5 to 2percent by weight of solids, calculated on the weight of the dry fibrousmaterial are deposited, drying the impregnated fibrous material andcuring it at a te. perature sufficient to convert the diglycidyl etherto the waterinsoluble state.

As water-soluble amines any primary, secondary or tertiary monoorpolyamine, which is water-soluble to the extent of at least 1.5% byweight may be employed. Examples are ethylene diamine,diethylenetriamine, triethylenetetramine dibutylamine,benzyldimethylamine, triethanolamine, cyclohexylamine,m-phenylenediamine, 2,4,6-tri-(dimethylaminornethyl)phenol andN,N-diethyl- 1,3-diaminopropane.

It is particularly preferred to use alkylene polyamines. These includethe compounds containing two amino groups which are joined together byan aliphatic bridge composed of m alkylene groups and m-l oxygen atoms,sulfur atoms or NH or N(alkyl) groups, situated between the saidalkylene groups (In being an integer). Different alkylene groups and/ orbridging groups situated between them may be present in the molecule ofsuch a polyamine.

Preferred alkylenepolyarnines are, therefore, ethylenediamine,diethylenetriamine, triethylenetetramine, tetraethylene pentamine,1,Z-diamino-Z-methylpropane, N,N- dimethyl-l,3-propylenediamine,tetramethyl-diethylenetriamine, pentamethyl-diethylenetriamine,di-(aminoethyl)- ether and di-(aminoethyl)-sulfide. There may also beemployed substituted alkylenepolyamines, for example those comprisingaliphatically saturated or unsaturated, preferably unbranched,hydrocarbon radicals, containing from 12 to 22 carbon atoms, which areattached to a nitrogen atom of the amine, either directly or throughbridge members, such as CO-groups, and those cornprising CN-radicals,or, preferably those comprising radicals of the formula n being aninteger from 1 to 10 and R a hydrogen atom, an alkyl radical or an acylradical.

In addition, amines obtainable by the addition of acrylonitrile toamines and reduction of the nitrile group 3,l54,429 Patented Oct. 27,1964 to the amine, and the substitution products thereof, are suitable.

Two or more amines of different kinds may be used in the aforesaidpreparations. For example, an alkylenepolyamine containing two primaryamino groups, such as triethylenetetramine, and an alkylenepolyaminecontaining at least two tertiary amino groups, such aspentamethyldiethylenetriamine or tetrahydroxyethylenediamine may beemployed.

Good wash resistance is obtained if approximately one active hydrogenatom of an amine is present per epoxide group of the diglycidylether.Thus for example, /6 mol of triethylenetetramine to one epoxide group ofthe diglycidylether is preferred, because the former contains six activehydrogen atoms. If an amine is employed which possesses no activehydrogen atoms attached to nitrogen, as in the case of theabove-mentioned tertiary amines, from 0.5 to 2, preferably 1, tertiaryamino groups of the tertiary amine is present per epoxide group.

The diglycidyl others are derived from polyethyleneglycois of thegeneral formula in which k represents an integer from about 7 to about35, i.e., polyethyleneglycols having an average molecular weight of 300to 1,500 preferably those having an average molecular weight of 300 to1000.

The use of diglycidyl ethers of polyethyleneglycols having the definedrange of molecular weight is critical. impregnating baths containingonly diglycidyl ethers of polyethyleneglycols having a molecular weightof less than 200-300 give dressings on polyester or polyacrylo nitrilefibers which, as compared to dressings obtained from baths containingthe defined diglycidyl ethers of higher polyethyleneglycols, are aboutten times less antistatic and, moreover, present a yellow appearance. Insome cases, preferably when using diglycidylethers of polyethyleneglycols having an average molecular Weight of 1000 to 1500, it isadvisable to use in addition minor amounts of a diglycidylether ofethylene glycol.

The diglycidyl others which are employed in accordance with theinvention correspond theoretically to the general formula in which krepresents an integer from about 7 to about 35. They are compounds whichcontain 11 1,2-epoxide groups calculated on the average molecularweight, n being an integer or a fractional number higher than 1. Theproducts possess from 1.1 to 2 epoxide groups per average molecularweight, and they are preferably obtained by reacting the definedpolyethylene glycols with epichlorhydrin in the presence of aFriedel-Crafts catalyst and subsequently dehydrohalogenating the productwith alkali.

The content of epoxide groups in the diglycidyl ethers is indicated, asusual for epoxy resins, by the number of mols of 1,2-epoxide groups perkg. of epoxide compound (epoxide equivalents/kg). Depending upon thenature of the polyethylene glycol employed and upon the reactionconditions in the preparation of the diglycidyl ethers, productscomprising 0.75 to 4.5 epoxide equivalents/kg. can be obtained.Preferably, diglycidyl ethers comprising 0.95 to 4 epoxideequivalents/kg. are employed.

The organic synthetic fibrous material treated by the process of thepresent invention will usually be hydrophobic in character and examplesare semisynthetic fibers such as cellulose ester fibers, for examplecellulose dior a triacetate, and fully synthetic fibers such aspolyacrylonitrile fibers, polyamide fibers, such as those consisting ofe-caprolactarn or of adipic acid and hexamethylene diamine, polyesterfibers of the glycol-terephthalic acid type, polyvinyl chloride fibersand polyvinylidene chloride fibers. Fibers consisting of copolymers, andfiber mixtures of different synthetic fibers or of synthetic and naturalfibers, may also usefully be 511Djtd to the treatment process of thepresent invention. There are preferably used polyamide,polyacrylonitrile and polyester fibers.

The aqueous preparations may be prepared by combining the necessaryconstituents in Water. Preferably, the aqueous preparations contain, per1,000 parts by weight of water, from 6 to 18 parts by weight of one ormore diglycidyl ethers of the type defined above and from 0.4 to 15parts, preferably from 0.8 to 8 parts by weight of one or morewater-soluble amines. Generally speaking, at most only a minorimprovement in antistatic properties, if any, is obtained when usingmore than 25 parts of diglycidyl ether. When less than three parts ofdiglycidyl ether are employed, the antistatic effects obtained aregenerally inadequate. The quantity of amine to be employed depends, asmentioned, primarily on the number of epoxide groups present. As a ruleof thumb, the above-indicated quantity of from 0.4 to 15 parts of amineholds good. If the excess of amine is too great, no wash-proofantistatic finish is obtained.

The impregnation of the synthetic fibrous material, e.g., textilefibers, with the aqueous preparations advantageously takes place at roomtemperature, for example by simply immersing or spraying, preferably ona padding machine. The impregnated fibrous material is passed throughsqueeze rolls to remove any excess solution and to ensure uniformimpregnation. The fibers are dried,

advantageously at moderate temperatures, for example between 30 C. and50 C. In some cases, the drying may be omitted and the fibrous materialexposed directly to relatively high temperatures to harden thediglycidyl ether. The impregnation is hardened at a temperaturesufiicient to convert the diglycidyl ether to the water-insoluble state.The higher the hardening temperature, the shorter is the time requiredfor the hardening treatment. Thus, at 40 C. the hardening may becontinued for about 4 hours, at 80 C. for from 1 to 1% hours, at 100 C.for from 20 to 30 minutes, and at 120 for about to minutes. Theimpregnations may also be cured at room temperatures, i.e., attemperatures from to C., the hardening time being about 24 hours.Temperatures lower than 15 C. are not recommended because the hardeningrequires too much time. Temperatures between 15 C. and 130 C. haveproved particularly satisfactory. The temperature may be even higher,for example 150, but the danger of yellowing of the fibers then arises.

The synthetic fibers are padded into the aqueous preparation, squeezedso that from 0.25% to 3%, preferably from 0.5% to 2% and moreparticularly about 1% of the solids, i.e., diglycidyl ether and amine,are deposited on the fibers, dried and hardened as indicated above. Theamount of solids deposited on the fibers is critical. When less thanabout 0.25 is present there are obtained insufiicint antistatic efiectsand when more than about 3% are deposited the fibers may acquire astiffening touch. The degree of squeezing depends on the fiber material,usually it is squeezed to a weight increase of between and 130% on theweight of the original fabric. As a rule, nylon, polyacrylonitrile andpolyester fibers are squeezed to a weight increase of 120%, and 80%.

Synthetic fibers treated by the process of the invention possess goodantistatic properties, which are substantially maintained even afterwashing.

In the following examples, where not otherwise stated, the parts areindicated by weight, the percentages by weight and the temperature indegrees centigrade.

The polyglycidyl ethers A to H mentioned in the examples are thefollowing products:

Epoxide equivalents/ kg. Diglycidyl ether A: from ethylene-glycol 4.0Diglycidyl ether B: from polyethylene-glycol 300 3.2 Diglycidyl ether C:from polyethylene-glycol 300 3.5 Diglycidyl ether D: frompolyethylene-glycol 300 3.75 Diglycidyl ether E: frompolyethylene-glycol 400 2.8 Diglycidyl ether F: from polyethylene-glycol600 1.45 Diglycidyl ether G: from polyethylene-glycol 1,000 0.95Diglycidyl ether H: from polyethylene-glycol 1,500 0.75

Example 1 6.2 parts of diglycidyl ether B and 0.5 part oftriethylenetetramine are dissolved in 365 parts of water to formimpregnating bath I. The same material, in the same quantities, aredissolved in 800 parts of water to form impregnating bath II.

A polyamide woven fabric is padded with impregnating bath I andtherefore squeezed to a weight increase of 55% on the weight of theoriginal fabric. The impregnated fabric is dried and the impregnation ishardened at 120 for 10 minutes.

A polyacrylonitrile fabric is impregnated on the padding machine withimpregnating bath II and squeezed to a weight increase of 120% on theweight of the original fabric and dried and hardened as in the case ofthe impregnating bath I.

The fabrics thus treated possess good antistatic properties, which arewash-resistant.

The same procedure is followed as above, with the difference that asolution of 5.6 parts of diglycidyl ether C and 0.5 part oftriethylene-tetramine, on the one hand in 355 parts of water(impregnating bath 1) and on the other hand in 740 parts of water(impregnating bath II) is used.

On the finished polyamide fabric, the specific surface resistanceamounts to 10 ohms. After washing five times each for hour with 5 g. ofsoap per liter at 50, the specific surface resistance amounts to 10ohms.

On the finished polyacrylonitrile fabric, the specific surfaceresistance is 10 ohms, and after washing five times it is 10 ohms.

In both cases, the specific surface resistance of the untreated fabricamounts to more than 10 ohms.

5.6 parts of diglycidyl ether C and 0.5 part of triethylene tetramineare dissolved in 490 parts of water. A polyester fabric of theglycol-terephthalic acid type is impregnated on the padding machine withthis bath and squeezed to a weight increase of on the weight of theoriginal fabric and dried and hardened at 125 C. for 10 minutes. On thefinished polyester fabric, the specific surface resistance is 10 ohms,and after washing five times it is 10 ohms. The untreated fabric has aresistance of about 10 ohms.

Example 2 4 parts of the compound of the formula:

and 9 parts of diglycidyl ether B are dissolved in 700 parts of water. Apolyamide fabric (nylon) is padded with this impregnating bath andsqueezed to a weight increase of 55% on the weight of the originalfabric. After drying and hardening for 10 minutes at the fabricpossesses Wash-resistant antistatic properties.

Example 3 6.9 parts of diglycidyl ether F, 2.5 parts of diglycidyl etherA and 0.5 part of triethylenetetramine are dissolved in 540 parts ofwater to form impregnating bath I and the same materials in the samequantities are dissolved in 1100 parts of water to form impregnatingbath II.

A polyamide fabric is padded with impregnating bath I, as described inExample 2, squeezed, dried and hardened.

A polyacrylonitrile fabric is padded with impregnating bath II andsqueezed to weight increase of 120% on the weight of the originalfabric. The fabric thus treated is dried, and the impregnation ishardened for minutes at 120.

In both cases, fabrics having good antistatic properties are obtained.

Example 4 A mixture of (a) 0.82 part of the compound of the formula C HNHCH CH CH NH (b) 1.24 parts of diglycidyl ether B,

(c) 0.5 part of diglycidyl ether A, and

(d) 0.05 part of triethylenetetramine is dissolved in 140 parts ofwater.

Polyamide fabric is padded with this impregnating bath and squeezed to aweight increase of about 55% based on the original weight of the fabric.The fabric is dried and the impregnation is hardened for 10 minutes at120.

The polyamide fabric thus obtained possesses good antistatic propertieswhich are wash-resistant.

Example 5 Polyamide fabrics are separately impregnated in baths, whichcontain each in 1,000 parts of water, the following (a) 10.1 parts ofdiglycidyl ether G, 7.2 parts of diglycidyl ether A and 0.96 part oftriethylenetetramine, (b) 11.1 parts of diglycidylether H, 6.1 parts ofdiglycidylether A and 0.83 part of triethylenetetramine.

In each case after squeezing to a weight reduction of 55% based on theoriginal weight of fabric, the fabrics are dried and then heated for 5minutes at 150.

Good wash-resistant anti-static finishes are obtained in all two cases.

Example 6 7.2 parts of diglycidyl ether E and 0.5 part oftriethylene-tetramine are dissolved in 500 parts of water. Polyamidefabric is impregnated squeezed to a weight increase of 58% and theweight of the original fabric dried and hardened for 10 minutes at 125.

The specific surface resistance of the finished fabric is 10 ohms, andafter washing is 10 ohms.

Example 7 10.1 parts of diglycidylether C and 2.4 parts of an additionproduct of 2 mol of ethylene oxide to 1 mol of diethylenetriamine aredissolved in 1,000 parts of water.

Polyester fabric is padded in the solution, squeezed to a weightincrease of 80% and the Weight of the original fabric dried and hardenedfor 5 minutes at 150.

The specific surface resistance of the finished fabric is 10 ohms, andafter washing remains at 10 ohms.

The specific surface resistance of the original fabric amounts to 10ohms.

Example 8 28.6 parts of diglycidylether C, 5.15 parts ofdiethylene-triamine and 20 parts of butanol are boiled under reflux for1 hour with stirring.

After addition of about 50 parts of water to the viscous product, thebutanol is removed by distillation with water in vacuo, and the residueis then brought to 67.5 parts with water.

3.3 parts of the highly water-soluble product obtained and 1.4 parts ofdiglycidyl ether C are dissolved together in 220 parts of water. Acellulose acetate fabric is impregnated in this bath, squeezed to aweight increase of 73% on the weight of the original fabric and hardenedfor 10 minutes at 120125.

A good wash-resistant antistatic finish is obtained.

G Example 9 1.7 parts of diglycidyl ether C, 0.05 part oftriethylenetetramine and 0.35 part of pentamethyldiethylenetriamine aredissolved in 76 parts of water.

A fabric consisting of polyvinylchloride is impregnated with thissolution, squeezed to a weight increase of 40% on the weight of theoriginal fabric, dried and thereafter maintained for 20 hours at 40-45 Agood wash-resistant antistatic finish is obtained.

Example 10 2 parts of diglycidyl ether D and 0.2 part of triethylenetetramine are dissolved in 110 parts of water to form impregnating bathI, the same materials in the same quantities are dissolved in 240 partsof water to form impregnating bath II, and the same materials in thesame quantities are dissolved in 160 parts of water to form impregnatingbath III.

A polyamide fabric is impregnated with impregnating bath 1, squeezed toincrease in weight and dried for 15 to 30 minutes.

A polyacrylonitrile fabric is impregnated with impregnating bath II,squeezed to 120% increase in weight and dried for 15 to 30' minutes.

A polyester fabric is impregnated with impregnating bath III, squeezedto 80% increase in weight and dried for 15 to 30 minutes.

The treated fabrics are left at room temperature, i.e., about 20 C. Fromtime to time test samples of these fabrics are each washed with 5 gramsof soap in a liter of water for 30 minutes at 50 C., and the specificsurface resistance measured.

The following table shows that after storage for 24 hours the dressingsare fast to washing, i.e., the antistatic eifect is practically the samebefore and after washing.

Specific surface resistance in ohms Polyamide Polyacrylo- Polyesterfabric nitrile fabric fabric Dried, unwashed 10 10 10 Dried, washedimmediately 10 10 10 Dried, washed after 8 hours 10 10 10 Dried, washedafter 24 hours. 10 10 10 Dried, washed after 6 days 10- 10 10 Untreated10 10 10 Example 11 This example shows the difference of antistaticeffects obtained by treating synthetic fibers with (1) a bath containinga diglycidylether of polyethylene glycol 300 and (2) a bath containing adiglycidylether of ethylene glycol Y only.

The fibers are padded and squeezed according to the following data:

Bath containing in 1,000 parts of Water Pick-up, Fibers Parts of Partsof Parts of percent diglydiglytricidyl cidyl ethylene ether C ether Atramine Poly 1.82 55 2. 1 55 0.83 120 0. 96 120 1. 25 1. 44 80 Thefibers are hardened for 10 minutes at -125 C.

Samples of the treated fibers are washed 5 times for /2 hour each timewith 5 g. of soap per liter at 50 C.

The specific surface resistance amounts to the following values.

What is claimed is:

1. A process for producing a wash-proof antistatic finish on organichydrophobic synthetic fibers which comprises impregnating said fiberswith an aqueous preparation containing, as the only active ingredients,per 1000 parts by weight of water,

(a) 3 to 25 parts by weight of a water-soluble diglycidyl ether of apolyethylene glycol having an average molecular weight of 300 to 1500,which diglycidyl ether contains 0.75 to 4.5 epoxide equivalents per kg.,as such, and

(b) 0.4 to 15 parts by weight of a water-soluble amine, squeezing thefibers to such an extent that from about 0.5 to 2 percent by weight ofsolids, calculated on the weight of the dry fibrous material, aredeposited, drying the impregnated fibers and curing the impregnatedmaterial at a temperature suificient to convert the diglycidyl ether tothe water-insoluble state.

2. A process for producing a wash-proof antistatic finish on organichydrophobic synthetic fibers which comprises impregnating said fiberswith an aqueous preparation containing, as the only active ingredients,per 1000 parts by weight of water,

(a) 3 to 25 parts by weight of a Water-soluble diglycidyl ether of apolyethylene glycol having an average molecular weight of 300 to 1500,which diglycidyl ether contains 0.75 to 4.5 epoxide equivalents per kg,and

(b) 0.4 to 15 parts by weight of a water-soluble alkylenepolyamine, assuch,

squeezing the fibers to such an extent that from about 0.5 to 2 percentby weight of solids, calculated on the weight of the dry fibrousmaterial, are deposited, drying the impregnated fibers and curing theimpregnated material at a temperature sufiicient to convert thediglycidylether to the water-insoluble state.

3. A process for producing a wash-proof antistatic finish on organichydrophobic synthetic fibers selected from the group consisting ofpolyamides, polyacrylonitriles and polyesters which comprisesimpregnating said fibers with an aqueous preparation containing, as theonly active ingredients, per 1,000 parts by weight of water,

(a) 6 to 18 parts by weight of a water-soluble diglycidyl ethercontaining 3.2 to 3.75 epoxide equivalents per kg. of apolyethyleneglycol having an average molecular weight of 300, and

(b) 0.8 to 8 parts by weight of triethylenetetramine,

as such,

squeezing the fibers to such an extent that from about 0.5 to 2 percentby weight of solids, calculated on the weight of the dry fibrousmaterial, are deposited, drying the impregnated fibers and curing theimpregnated material at a temperature sufficient to convert thediglycidylether to the water-insoluble state.

4. A process for producing a wash-proof antistatic finish on hydrophobicsynthetic polyester fibers which comprises impregnating said fibers withan aqueous preparation containing as the only active ingredients, per1,000 parts by weight of water,

(a) 10 to 13 parts by weight of a water-soluble diglycidyl ethercontaining 3.2 to 3.75 epoxide equivalents per kg. of apolyethyleneglycol having an average molecular weight of 300, and

(b) 1 to 1.3 part by weight of triethylenetetramine,

as such,

squeezing the fibers to such an extent that from about 0.5 to 2 percentby weight of solids, calculated on the weight of the dry fibrousmaterial, are deposited, drying the impregnated fibers and curing theimpregnated material at a temperature sufiicient to convert thediglycidyl ether to the water-insoluble state.

5. A process for producing a wash-proof antistatic finish on hydrophobicsynthetic polyamide fibers which comprises impregnating said fibers withan aqueous preparation containing, as the only active ingredients, per1,000 parts by weight of water,

(a) 15 to 18 parts by weight of a water-soluble diglycidyl ethercontaining 3.2 to 3.75 epoxide equivalents per kg. of a polyethyleneglycol having an average molecular weight of 300, and

(b) 1.5 to 1.8 parts by weight of triethylene tetramine,

a such,

squeezing the fibers to such an extent that from about 0.5 to 2 percentby weight of solids, calculated on the weight of the dry fibrousmaterial, are deposited, drying the impregnated fibers and curing theimpregnated material at a temperature sufiicient to convert thediglycidyl ether to the water-insoluble state.

6. A process for producing a wash-proof antistatic finish on hydrophobicpolyacrylonitrile fibers which comprises impregnating said fibers withan aqueous preparation containing, as the only active ingredients, per1,000 parts by weight of water,

(a) 7 to 8.5 parts by weight of a water-soluble diglycidyl ethercontaining 3.2 to 3.75 epoxide equivalents per kg. of polyethyleneglycol having an average molecular weight of 300, and

(b) 0.6 to 0.8 part by weight of triethylene tetrarnine,

as such,

squeezing the fibers to such an extent that from about 0.5 to 2 percentby weight of solids, calculated on the weight of the dry fibrousmaterial, are deposited, drying the impregnated fibers and curing theimpregnated material at a temperature sufficient to convert thediglycidyl ether to the water-insoluble state.

7. An organic synthetic hydrophobic textile fiber having applied theretoin an amount of 0.5 to 2 percent calculated on the weight of said fiberthe product obtained by reacting exclusively a water-soluble amine, assuch with a water-soluble diglycidyl ether of a polyethylene glycolhaving an average molecular Weight of 300 to 1500, which diglycidylethercontains 0.75 to 4.5 epoxide equivalents per kg.

8. An organic synthetic hydrophobic textile fiber having improvedantistatic properties coated with the product obtained by reactingexclusively a water-soluble alkylenepolyamine, as such, with awater-soluble diglycidyl ether of a polyethylene glycol having anaverage molecular weight of 300 to 1500, which diglycidylether contains0.75 to 4.5 epoxide equivalents per kg., the amount of the coating beingfrom 0.5 to 2 percent calculated on the weight of said fiber.

9. An organic synthetic hydrophobic textile fiber having improvedantistatic properties coated with the product obtained by reactingexclusively a Water-soluble alkylenepolyamine, as such, with awater-soluble diglycidylether of a polyethylene glycol having an averagemolecular weight of 300 to 1500, which diglycidylether contains 0.75 to4.5 epoxide equivalents per kg., the amount of the coating being fromabout one percent calculated on the weight of said fiber.

References Cited in the file of this patent UNITED STATES PATENTSSchroeder Sept. 8, 1959

1. A PROCESS FOR PRODUCING A WASH-PROOF ANTISTATIC FINISH ON ORGANICHYDROPHOBIC SYNTHETIC FIBERS WHICH COMPRISES IMPREGNATING SAID FIBERSWITH AN AQUEOUS PREPARAION CONTAINING, AS THE ONLY ACTIVE INGREDIENTS,PER 1000 PARTS BY WEIGHT OF WATER, (A) 3 TO 25 PARTS BY WEIGHT OF AWATER-SOLUBLE DIGLYCIDYL ETHER OF A POLYETHYLENE GLYCOL HAVING AVERAGEMOLECULAR WEIGHT OF 300 TO 1500, WHICH DIGLYCIDYL ETHER CONTAINS 0.75 TO4.5 EPOXIDE EQUIVALENTS PER KG., AS SUCH AND (B) 0.4 TO 15 PARTS BYWEIGHT OF A WATER-SOLUBLE AMINE, SQUEEZING THE FIBERS TO SUCH AN EXTENTTHAT FROM ABOUT 0.5 TO 2 PERCENT BY WEIGHT OF SOLIDS, CALCULATED ON THEWEIGHT OF THE DRY FIBROUS MATERIAL, ARE DEPOSITED, DRYING THEIMPREGNATED FIBERS AND CURING THE IMPREGNATED MATERIAL AT A TEMPERATURESUFFICIENT TO CONVERT THE DIGLYCIDYL ETHER TO THE WATER-INSOLUBLE STATE.